1. Field of the Invention
The technical field of the present invention relates to a power storage device and a manufacturing method thereof.
2. Description of the Related Art
With an increase in concern for the environmental issues, power storage devices used for power supply for hybrid vehicles, such as secondary batteries and electric double layer capacitors, have been actively developed. As the power storage devices, a lithium-ion secondary battery and a lithium ion capacitor which have high energy performance have attracted attention. The lithium-ion secondary battery, which is compact but can store large electricity has been already mounted on a portable information terminal such as a mobile phone or a notebook personal computer, and has helped miniaturization of products.
The secondary battery and the electric double layer capacitor have a basic structure in which an electrolyte is provided between a positive electrode and a negative electrode. It is known that each of the positive electrode and the negative electrode includes a current collector and an active material provided over the current collector. For example, in a lithium-ion secondary battery, a material capable of insertion and extraction of lithium ions is used as an active material.
Various approaches to improve the characteristics of a power storage device have been taken. For example, study of a positive electrode active material is one of the approaches to improve the characteristics of a power storage device (for example, see Patent Document 1).
[Reference]
[Patent Document]
    [Patent Document 1] International Publication WO 2006/049001 Pamphlet
An object of one embodiment of the present invention is to provide a positive electrode active material that improves the characteristics of a power storage device. Another object of one embodiment of the present invention is to provide a manufacturing method of the positive electrode active material that improves the characteristics of a power storage device.
Another object of one embodiment of the present invention is to provide a power storage device whose characteristics are improved. Another object of one embodiment of the present invention is to provide a manufacturing method of the power storage device whose characteristics are improved.